ISAKOS: 2019 Congress in Cancun, Mexico
ISAKOS

2019 ISAKOS Biennial Congress ePoster #742

 

Bicruciate Lesion Biomechanics – Treatment Using a Simultaneous Tensioning Protocol: ACL Fixation First is Better than PCL Fixation First to Restore Tibiofemoral Orientation

Carlos E. D. Franciozi, MD, PhD, Prof., São Paulo, SP BRAZIL
Rogerio T. Carvalho, MD, São Paulo, SP BRAZIL
Yasuo Itami, MD, Takatsuki JAPAN
Michelle H. McGarry, MS, Long Beach, CA UNITED STATES
Sheila J. M. Ingham, MD, PhD, São Paulo, SP BRAZIL
Rene J. Abdalla, MD, PhD, São Paulo, SP BRAZIL
James E. Tibone, MD, Los Angeles, CA UNITED STATES
Thay Q. Lee, PhD, Pasadena, CA UNITED STATES

Federal University of São Paulo, São Paulo, SP, BRAZIL

FDA Status Cleared

Summary

Bicruciate reconstruction using simultaneous tensioning of the ACL and PCL grafts, with ACL graft fixation first, restores closer to normal tibiofemoral orientation and may lead to superior results in comparison to the “gold-standard” PCL fixation first tightening sequence.

Abstract

Purpose

Bicruciate lesions are combined anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) injuries. An uncommon technique for bicruciate ligament reconstruction involving simultaneous tensioning of the ACL and PCL grafts, with ACL graft fixation prior to PCL graft fixation, has been pointed out as superior to the “gold-standard” PCL graft fixation first. The purpose of this study was to compare tibiofemoral biomechanics between ACL graft fixation first and PCL graft fixation first in a simultaneous tensioning protocol for bicruciate ligament reconstruction.

Methods

Twelve fresh-frozen cadaveric knees (six matched pairs) were tested using a custom testing system. Neutral tibial position representing tibiofemoral orientation, anterior-posterior (AP) tibial translation, varus-valgus laxity, and internal-external rotation were measured using a Microscribe 3DLX at 0°, 30°, 60°, and 90° of knee flexion. The following knee conditions were evaluated: intact, bicruciate deficient, and following bicruciate reconstruction. Single bundle PCL reconstruction was performed using a bone-plug quadriceps tendon graft and single bundle ACL reconstruction was performed using a quadruple strand hamstrings graft. PCL graft fixation was always performed at 90° of flexion and ACL graft fixation was always performed at full extension. A simultaneous tensioning protocol was used for graft fixation, in the bicruciate reconstruction, maintaining simultaneous tension to both grafts. Two distinctive graft fixation orders, using the simultaneous tensioning protocol, were evaluated: PCL fixation first was compared to ACL fixation first. A paired t-test was used to compare the differences between both fixation groups. A t-test sample size calculation was performed based on the average from the first two specimens resulting in 6 specimens needed for testing for a power of 0.8 and an alpha of 0.05.

Results

ACL fixation first achieved a tibiofemoral orientation closer to the intact knee than PCL fixation first at 90° of flexion (1.8±1.6mm vs. 6.1±3.2mm, p=0.016). This difference was statistically and also clinically significant due to its magnitude. PCL fixation first had a larger decrease in AP translation than ACL fixation first at 30° of flexion (64.6±3.5% vs. 58.3±2.4%, p=0.01), however, this difference was not clinically relevant. No significant differences were found for varus/valgus, external-internal rotation decrements after bicruciate reconstruction nor for AP translation, varus/valgus and internal/external rotation increase after bicruciate lesion comparing ACL fixation first to PCL fixation first.

Conclusion

Bicruciate ligament reconstruction using a simultaneous tensioning protocol with ACL fixation first at full extension, followed by PCL fixation at 90°, resulted in a closer to normal tibiofemoral orientation. This study may help guide surgeons in decision making for the graft tensioning protocol and fixation sequence in a bicruciate ligament reconstruction.
CLINICAL RELEVANCE: Bicruciate reconstruction using simultaneous tensioning of the ACL and PCL grafts with ACL graft fixation first may lead to superior results in comparison to the “gold-standard” PCL fixation first tightening sequence in the clinical setting.